Stasi R, Stipa E, Masi M, Oliva F, Sciarra A, Perrotti A, Olivieri M, Zaccari G, Gandolfo G M, Galli M
Department of Hematology, University of Rome Tor Vergata, S. Eugenio Hospital, Italy.
Blood. 1994 Dec 15;84(12):4203-8.
Antibodies against phospholipid antigens (APA) have been demonstrated in idiopathic thrombocytopenic purpura (ITP), but their clinical and pathogenetic significance has remained elusive. In this study we analyzed the prevalence and clinical features of ITP patients with elevated APA. In addition, we prospectively evaluated APA levels after treatment with corticosteroids and compared them with platelet-associated immunoglobulin (PAIgG) titers. We studied 149 patients with newly diagnosed ITP. Of these, 78 had a platelet count less than 50 x 10(9)/L and received an initial treatment with oral prednisone (PDN). In 71 asymptomatic cases with platelet counts between 50 x 10(9)/L and 120 x 10(9)/L, no therapy was scheduled. However, in five of them, the platelet count fell below 50 x 10(9)/L after more than 12 months; these patients were treated with PDN. Tests for APA included the measurement of anticardiolipin antibodies (ACA) with a solid-phase immunoassay and the detection of the lupus-like anticoagulant (LA) activity with coagulation tests that included kaolin-clotting time, dilute Russel's Viper venom time, activated partial thromboplastin time (aPTT), and dilute aPTT. Controls consisted of 174 apparently healthy subjects. Either LA or elevated ACA was seen in 69 patients (46.3%) at diagnosis. LA and ACA were both elevated in 24 cases (16.1% of the overall patient population and 34.8% of patients with high APA concentrations). No correlation was found between LA ratio values and ACA-IgG or -IgM titers, or between ACA-IgG and ACA-IgM levels. The presence of these antibodies was not associated with sex, age, platelet count, or the severity of hemorrhages. PAIgG was detected in 106 of 127 cases (83%). Again, no relationship was observed with clinical parameters or with APA levels. However, all cases with elevated APA also had increased PAIgG. With regard to the clinical course, we were not able to detect any significant difference between patients with normal and elevated APA. An initial complete response to prednisone treatment was observed in 43 of 83 cases (51.8%), with 13 (15.7%) achieving a prolonged complete remission. APA levels were not significantly modified after PDN therapy and on relapse. We conclude that APA positivity is a common finding in patients with ITP and does not select a category with different clinical features. APA levels are not influenced by immunosuppressive therapy with steroids and are not related to the activity of the disease. Therefore, we do not support a role for APA in the pathogenesis of ITP.
抗磷脂抗原（APA）抗体已在特发性血小板减少性紫癜（ITP）中得到证实，但其临床和发病机制意义仍不明确。在本研究中，我们分析了APA升高的ITP患者的患病率和临床特征。此外，我们前瞻性评估了皮质类固醇治疗后APA水平，并将其与血小板相关免疫球蛋白（PAIgG）滴度进行比较。我们研究了149例新诊断的ITP患者。其中，78例血小板计数低于50×10⁹/L，接受口服泼尼松（PDN）初始治疗。71例无症状患者血小板计数在50×10⁹/L至120×10⁹/L之间，未安排治疗。然而，其中5例在12个月以上后血小板计数降至50×10⁹/L以下；这些患者接受了PDN治疗。APA检测包括用固相免疫测定法测量抗心磷脂抗体（ACA），以及用包括高岭土凝血时间、稀释罗素蝰蛇毒时间、活化部分凝血活酶时间（aPTT）和稀释aPTT的凝血试验检测狼疮样抗凝物（LA）活性。对照组由174名明显健康的受试者组成。诊断时69例患者（46.3%）出现LA或ACA升高。24例患者LA和ACA均升高（占全部患者的16.1%，占APA浓度高的患者的34.8%）。未发现LA比值与ACA-IgG或-IgM滴度之间，或ACA-IgG与ACA-IgM水平之间存在相关性。这些抗体的存在与性别、年龄、血小板计数或出血严重程度无关。127例中的106例（83%）检测到PAIgG。同样，未观察到与临床参数或APA水平的关系。然而，所有APA升高的病例PAIgG也升高。关于临床病程，我们未能检测到APA正常和升高的患者之间有任何显著差异。83例中的43例（51.8%）观察到对泼尼松治疗的初始完全缓解，其中13例（15.7%）实现了长期完全缓解。PDN治疗后及复发时APA水平无显著改变。我们得出结论，APA阳性在ITP患者中是常见发现，并不区分具有不同临床特征的类别。APA水平不受类固醇免疫抑制治疗的影响，且与疾病活动无关。因此，我们不支持APA在ITP发病机制中的作用。
